Lock



Jan. 21, 1936. J BREEN ET AL 2,028,495

LOCK

Filed Jan. 25, 1955 XML A T TORNE Y Patented Jan. 21, 1936 UNITED STATES PATENT OFFICE LOCK Application January 23, 1935, Serial No. 3,108

v the enclosure.

Another object of the invention. is to cause an alarm to be sounded upon a key being trapped. It is, of course, well known that unscrupulous persons often attempt to gain access to locked enclosures for fraudulent purposes by picking the lock. In order to defeat such attempts improvements in the lock mechanisms, in order to render them as nearly as possible pick'proof, have been made from time to time. Itquite often happens, however, that unscrupulous persons come into possession of the proper key for unlocking a certain lock and pick-proofing arrangements are, of course, no protection against such persons.

According to a feature of the invention, should an unauthorized person, who has come into possession of a key as above mentioned, attempt to utilize such key to operate the associated look, not only is the lock held in a locked condition but the key itself is trapped in the lock and. its removal by the unauthorized holder isprevented. Means are included, however, whereby an authorized person may collect the key, that is, remove it from the lock, without damaging the lock or the enclosure in any way. The collected key is then, of course, returned to the proper authorities.

In accordance with another feature of the invention, an alarm may be sounded upon a key being trapped which alarm may be instrumental in causing the apprehension of the person using the key for fraudulent purposes.

Locks of the nature contemplated by the invention may be used, to mention one specific application, on telephone coin collectors of the general type disclosed in Forsberg U. S. Patent 1,043,219 of November 5, 191-2 In. accordance with a preferred arrangement of the lock contemplated. by the invention, a spring member is mounted on the outer case of the lock, a portion of the member projecting through an opening in the case and normally resting on the surfaceof the bolt. Now when an attempt is made to unlock the lock, the key is inserted and rotated which tends to retract the bolt. As the bolt starts its retracting movement, however, a hole therein is brought into registry with the end of the spring member which thereupon drops into the hole and arrests the movement of the bolt. Theend of the spring member resting in the hole in the bolt not only prevents further retraction of the bolt to unlock the lock but also prevents movement of the bolt in the opposite direction to its previous position. The unauthorized holder of the key is therefore prevented fromunlocking the lock and also from rotating the key back to the pointwhere it could be removed from the lock.

In order thatauthorized persons may be able to remove the trapped key without damaging the lock itself or the locked enclosure, an aperture is preferably provided in the case of the locked enclosure through which a tool may be inserted. to raise the spring member thereby lifting the end thereof out of the hole in the bolt and releasing the bolt for movement in either direction.

A thorough understanding of the operation of the contemplated arrangement and an appreciation of the various features thereof may be gained from a. consideration of thefollowing detailed description in connection with the attached drawing in which: V

Figure 1 is atop view of a lock provided with key trapping means in accordance with the invention;

Fig. 3 isa bottom view of the lock shown in Fig. 1, the cover of. the lock being removed to show the bolt. key barrel .and tumbler of the lock;-

Figre is a top view of the lock with the bolt partially retracted-,a portion of the case being broken away;

Fig. 5 isa bottom view of the lock as shown in Fig. 4;.

Fig.- fizisa rear view of. a part of a telephone is an end view of the lock shown in .coin collector, aportion of the case being removed torshow the lockin position, a tool for freeing a trapped key also being shown;-

Fig. '7 is a topview of a. lock of the type shown in Fig. 1, modified. to include alarm controlling means; and i Fig. 8 is aside view of the lock shown in Fig. 6. Referring now-to Fig.- 1, a lock H is shown in normal locked condition, that is with the bolt I2 in fullyextended position. The inner mechanism of the lock including the tumblers, bolt, key barrel, etc. may be of any standard construction such, for example, as that fully disclosed in Shann U. S. Patent 1,793,254, issued February 17, 1931. While it is not believed necessary to describe these parts of the lock, or their operation, in detail it might be pointed out, in order to aid in the understanding of the key trapping means with which the invention is concerned, that key barrel I3 is provided with projection l4 (see Fig. 3) which, when the barrel is rotated, strikes shoulder l5 provided on bolt [2 and causes retraction thereof. A plurality of key operated tumblers or levers 16 (only one shown to avoid complicating the drawing unnecessarily) are arranged adjacent the key barrel having faces of different lengths to correspond to notches in the operating key. The lower portions of the tumblers have projections which extend into the path of lug I! provided on bolt [2 and prevent retraction thereof unless the projections are aligned and withdrawn from the path of the lug by rotation of a properly designed key in the key barrel.

As usual in locks of this general type a portion N3 of the case is extended and encloses the key barrel 43, the edge of this extended portion overlapping the end of key slot 2! in such a way that a key of proper size for operating the lock can be fully inserted into the key slot, or removed therefrom, only if the barrel is in such a position that the end of the slot registers with recess 22 provided in extended portion I8. The barrel occupies this position only when bolt I2 is fully extended, that iswhen the lock is in normal locked condition.

A wire spring member 23 is mounted on lock H, one end being attached to mounting lug 24 while the other end 25 is bent at right angles to the major length of the wire, as clearly shown in Fig. 2, and, passing through hole 26 in the case of the lock, rests on the upper surface of bolt 12. A second wire spring member 21 is also mounted on the lock, each end of this spring being rigidly attached to mounting lugs 34 and 32, respectively. Member 21 passes over member 23 and is in contact therewith; the spring action of member 27 supplementing that of member 23 and insuring that end 25 remains in firm contact with the surface of bolt I2. I

Let us assume now, for purposes of description that a key 33 properly designed for operation of the lock, be inserted in key slot 2| and rotated in an attempt to unlock the enclosure. As the key barrel is rotated the tumblers are moved and retraction of the bolt is started as described in Shann U. S. 1,793,254 referred to above. Now, a hole 34 is provided in bolt l2 and as the bolt is retracted this hole is brought into registry with the end 25 of spring member 23 which, as described above, normally rests on the upper surface of the bolt. As this point of registry is reached the end of spring member 23, due to its own spring action and that of spring member 21, drops into hole 34, as shown in Fig. 4, and prevents further movement of bolt I2 in either direction. This action takes place before sufficient retraction of the bolt to unlock the enclosure and it will be apparent therefore that the user of the key is prevented from unlocking the lock. Further, he is prevented from removing the key from the lock as the key barrel, at the time the above action takes place, is in the position shown in Fig. 5. As shown the end of key slot 2! is not in registry with recess 22 and it has been pointed out above that the key cannot be removed until this point of registry is reached. The key barrel cannot, of course, be rotated as the bolt is held against movement as described above.

Assuming now that an authorized person visits the premises and wishes to remove the trapped key. Referring to Fig. 6 a portion of a telephone coin collector, which may be of the type described in Forsberg U. S. Patent 1,043,219, issued November 5, 1912, is shown. The look I l is shown in use for fastening the upper housing 35 of the 001- I lector to the lower housing 36. A hole 31 is provided in the side of the upper housing. The view is taken from the rear of the collector, the usual back plate being omitted to facilitate illustration of the invention. Itwill be understood, however, that this back plate is to be provided as usual and that it acts to close the rear openings of upper housing 35 and lower housing 36 and also that it cooperates with certain portions of the housings in such a manner that upper housing 35 cannot be removed from lower housing 36 unless bolt 12 of lock ll be fully retracted. It will be understood that wall 38 is securely attached, for example by Welding, to housing 36.

In order to free the key, the authorized person inserts tool 4! through hole 31 and utilizes the end of the tool to exert pressure on spring member23 in a manner to lift the end 25 out of hole 34. After this has been done the bolt is, of course, free to move in either direction if the key be rotated. The authorized person may therefore either rotate the key in the direction to unlock the lock or in the opposite direction to the point where the key may be removed.

In certain instances it may be desirable that an alarm be sounded upon a key being trapped in order that the key may be removed promptly and that apprehension of the person using the key fraudulently may be facilitated. A modification of the lock providing for the control of such an alarm is shown in Fig. 7 and Fig. 8.

As shown in Fig. 7, ground 42 is connected to spring 23 at the point of its attachment to lug 24. Contact .43 is positioned under spring 23 being separated electrically from the case of the look by insulator 44. Conductor 45 connects contact 43 to one terminal of alarm device 46, the other terminal of which is connected to battery 41. As shown in Fig. 8, when spring 23 is in normal position, that is with end 25 resting on the upper surface of the bolt as in Fig. 2, members 23 and 43 are not in contact. However, when end 25 of member 23 drops into hole, 34, the position of Fig. 4 whereby a key is trapped, contact is made between parts 23 and 43 thereby completing a circuit to energize alarm 46, this circuit being traced from battery 41, alarm 46, conductor 45, contact 43, spring 23 to ground 42. The alarm may be located on the premises or at a central oifice as desired.

While certain specific embodiments of the invention have been selected for detailed description, the invention is not, of course, limited in its application to the specific embodiments described.

tension on said barrel engaged with said shoulder for causing movement of said bolt as said barrel is rotated, said casing having a notch adjacent said barrel to permit the insertion of a key in said barrel only when said notch and said slot are in alignment, a key operated tumbler for controlling the retraction of the bolt and a spring member mounted on the exterior of the casing with one end thereof passing through said aperture, said spring member being biased to cause said one end to normally rest on the surface of the bolt, said bolt having a hole so located therein that after partial rotation of said barrel and partial retraction of the bolt said hole is brought into registry with the end of the spring member which thereupon enters the hole and prevents further movement of the bolt and further 5 rotation of said barrel.

JOHN RAYMOND BREEN. ARLINGTON S. STRAUSBACH. 

